Re: CAUSATION IN PHYSICS

["John S. Denker" <jsd@MONMOUTH.COM>]

At 09:47 AM 10/17/00 +1100, Brian McInnes wrote:
...
> We can then use that acceleration, the known mass of the object, and
> the relation F=ma to calculate the value of the contact force exerted
> by the wheel on the object.

OK, it's physics up to this point.  We are calculating observable quantities.

> What is causing this observed change
> of motion (Newton's first law) is a contact force between the wheel
> and the object that has arisen in the attachment process

That last statement is inconsistent with Hume's definition of
cause-and-effect, as presented in
  http://www.britannica.com/bcom/eb/article/0/0,5716,108560+8+106052,00.html
(thanks, Bernard).

The definition requires temporal priority of the cause.  In this case we
can calculate the force and the acceleration, and Newton's laws require
_no_ time difference between force and acceleration.

Brian:  If you are using some other definition of cause-and-effect, please
explain what it is.